Ultrasound-guided Modified Thoracoabdominal Nerve Plane Block (M-TAPA) is performed into the costochondral aspect at the 9th-10th costal level by injecting local anesthetics deep into the chondrium. It provides blockage of both the anterior and lateral cutaneous branches of the thoracoabdominal nerve. Studies show that M-TAPA block is effective for postoperative analgesia and other abdominal surgeries, but its effect on patients undergoing LSG surgery has not yet been studied. The hypothesis is that the M-TAPA block performed in patients undergoing Laparoscopic Sleeve Gastrectomy (LSG) Operation would reduce opioid consumption in the first 24 hours period after surgery.